Safe, High-Performance, Polymer Electrolyte for Lithium Batteries

One of the key barriers to the wide-spread use of lithium-ion batteries is its potential for catastrophic failure due to their lack of inherent abuse tolerance. When cells are thermally or electrically abused, their temperature can rise and exothermic reactions between the combustible, liquid electrolyte and the charged electrodes can cause the cells to undergo thermal runaway. There is a clear need for a more stable Lithium-ion battery electrolyte. The aim of this project is to synthesize and process a non-flammable, solid battery electrolyte and to demonstrate stability up to 5 V, ultimately presenting further ability for the development of safer high power lithium batteries that rely on high voltage cathodes. Dr. Kofinas’ research group at University of Maryland has developed a novel hybrid polymer electrolyte that promises the conductivity of a conventional liquid electrolyte with the low volatility and mechanical properties of a solid.

The risks of battery leakage and presence of combustible/corrosive components give rise to safety concerns, which have present an unacceptable risk in the use of lithium batteries. The highly reactive nature of these electrolytes necessitates the use of protective enclosures that separate the battery from the user as well as the environment limiting the internal vapor pressure to safe levels, and engineering safety measures which add to the size and bulk of the battery. Comparatively, a polymer electrolyte based battery system would only require a thin laminating layer, to shield it from external elements. Additionally, battery power would benefit greatly from the conformal and safe nature of all-solid polymer electrolyte based energy sources. Development has been hampered by the lack of solid-state materials possessing acceptable levels of safety and capacity. The ease of processing a shape-conforming polymer electrolyte would allow the production of thin film flexible batteries that could be wound into coils or processed as coatings and sheets, thus providing large area devices with integrated electronics.